2004-01-28 06:58 AM
2011-05-17 02:58 AM
2011-05-17 02:58 AM
Please see the attached document on how sector swap works during Reset.
2011-05-17 02:58 AM
Oops, the document didn't get attached with the last one.
2011-05-17 02:58 AM
Moderator,
Thanks for the help with that. I've gotten a bit further. I specified for both the boot-loader program and the main application image that the linker locate the reset code at the same address. Also, I've figured out (despite my assembler-phobia) how to modify the startup code to change the VM register and page values. I have one more question, however. Can I depend on the internal uPSD SRAM having any known values at power-up? For instance, what I would like to do is have the startup code run the bootloader. If the bootloader finds a valid application image, it will store a new VM and page value in SRAM and then reset. The startup code will then load this value into the registers and run the specified image. The question is how do I check whether these values have been set by the bootloader, or if the device has just been powered on? Will the SRAM power-up as all 0x00's or all 0xFF's, or just be competely random? I think this is the last hurdle in my design. Thanks. Best Regards, pHaze4262011-05-17 02:58 AM
uPSD's internal SRAM are volatile and at power up, the values are completely random. However, you do have the option to use a battery to back-up the SRAM content when your target power goes down. You can also design a battery recharge circuitry to charge your battery when your target is powered.